![\"\u70b9\u51fb\u67e5\u770b\u539f\u56fe\"](\"\/notes\/content\/uploadfile\/201506\/f3cc1433603318.jpg\")
<\/a><\/a><\/p>\n\u7cfb\u7edf\u6a21\u578b\u5982\u56fe\u6240\u793a\uff1a<\/p>\n
1.\u6700\u7ec8\u4e00\u81f4\u6027\uff1aclient\u4e0d\u8bba\u8fde\u63a5\u5230\u54ea\u4e2aServer\uff0c\u5c55\u793a\u7ed9\u5b83\u90fd\u662f\u540c\u4e00\u4e2a\u89c6\u56fe\uff0c\u8fd9\u662fzookeeper\u6700\u91cd\u8981\u7684\u6027\u80fd\u3002<\/p>\n 2 .\u53ef\u9760\u6027\uff1a\u5177\u6709\u7b80\u5355\u3001\u5065\u58ee\u3001\u826f\u597d\u7684\u6027\u80fd\uff0c\u5982\u679c\u6d88\u606fm\u88ab\u5230\u4e00\u53f0\u670d\u52a1\u5668\u63a5\u53d7\uff0c\u90a3\u4e48\u5b83\u5c06\u88ab\u6240\u6709\u7684\u670d\u52a1\u5668\u63a5\u53d7\u3002<\/p>\n 3 .\u5b9e\u65f6\u6027\uff1aZookeeper\u4fdd\u8bc1\u5ba2\u6237\u7aef\u5c06\u5728\u4e00\u4e2a\u65f6\u95f4\u95f4\u9694\u8303\u56f4\u5185\u83b7\u5f97\u670d\u52a1\u5668\u7684\u66f4\u65b0\u4fe1\u606f\uff0c\u6216\u8005\u670d\u52a1\u5668\u5931\u6548\u7684\u4fe1\u606f\u3002\u4f46\u7531\u4e8e\u7f51\u7edc\u5ef6\u65f6\u7b49\u539f\u56e0\uff0cZookeeper\u4e0d\u80fd\u4fdd\u8bc1\u4e24\u4e2a\u5ba2\u6237\u7aef\u80fd\u540c\u65f6\u5f97\u5230\u521a\u66f4\u65b0\u7684\u6570\u636e\uff0c\u5982\u679c\u9700\u8981\u6700\u65b0\u6570\u636e\uff0c\u5e94\u8be5\u5728\u8bfb\u6570\u636e\u4e4b\u524d\u8c03\u7528sync()\u63a5\u53e3\u3002<\/p>\n 4 .\u7b49\u5f85\u65e0\u5173\uff08wait-free\uff09\uff1a\u6162\u7684\u6216\u8005\u5931\u6548\u7684client\u4e0d\u5f97\u5e72\u9884\u5feb\u901f\u7684client\u7684\u8bf7\u6c42\uff0c\u4f7f\u5f97\u6bcf\u4e2aclient\u90fd\u80fd\u6709\u6548\u7684\u7b49\u5f85\u3002<\/p>\n 5.\u539f\u5b50\u6027\uff1a\u66f4\u65b0\u53ea\u80fd\u6210\u529f\u6216\u8005\u5931\u8d25\uff0c\u6ca1\u6709\u4e2d\u95f4\u72b6\u6001\u3002<\/p>\n 6 .\u987a\u5e8f\u6027\uff1a\u5305\u62ec\u5168\u5c40\u6709\u5e8f\u548c\u504f\u5e8f\u4e24\u79cd\uff1a\u5168\u5c40\u6709\u5e8f\u662f\u6307\u5982\u679c\u5728\u4e00\u53f0\u670d\u52a1\u5668\u4e0a\u6d88\u606fa\u5728\u6d88\u606fb\u524d\u53d1\u5e03\uff0c\u5219\u5728\u6240\u6709Server\u4e0a\u6d88\u606fa\u90fd\u5c06\u5728\u6d88\u606fb\u524d\u88ab\u53d1\u5e03\uff1b\u504f\u5e8f\u662f\u6307\u5982\u679c\u4e00\u4e2a\u6d88\u606fb\u5728\u6d88\u606fa\u540e\u88ab\u540c\u4e00\u4e2a\u53d1\u9001\u8005\u53d1\u5e03\uff0ca\u5fc5\u5c06\u6392\u5728b\u524d\u9762\u3002<\/p>\n Zookeeper\u7684\u6838\u5fc3\u662f\u539f\u5b50\u5e7f\u64ad\uff0c\u8fd9\u4e2a\u673a\u5236\u4fdd\u8bc1\u4e86\u5404\u4e2aServer\u4e4b\u95f4\u7684\u540c\u6b65\u3002\u5b9e\u73b0\u8fd9\u4e2a\u673a\u5236\u7684\u534f\u8bae\u53eb\u505aZab\u534f\u8bae\u3002Zab\u534f\u8bae\u6709\u4e24\u79cd\u6a21\u5f0f\uff0c\u5b83\u4eec\u5206\u522b\u662f\u6062\u590d\u6a21\u5f0f\uff08\u9009\u4e3b\uff09\u548c\u5e7f\u64ad\u6a21\u5f0f\uff08\u540c\u6b65\uff09\u3002\u5f53\u670d\u52a1\u542f\u52a8\u6216\u8005\u5728\u9886\u5bfc\u8005\u5d29\u6e83\u540e\uff0cZab\u5c31\u8fdb\u5165\u4e86\u6062\u590d\u6a21\u5f0f\uff0c\u5f53\u9886\u5bfc\u8005\u88ab\u9009\u4e3e\u51fa\u6765\uff0c\u4e14\u5927\u591a\u6570Server\u5b8c\u6210\u4e86\u548cleader\u7684\u72b6\u6001\u540c\u6b65\u4ee5\u540e\uff0c\u6062\u590d\u6a21\u5f0f\u5c31\u7ed3\u675f\u4e86\u3002\u72b6\u6001\u540c\u6b65\u4fdd\u8bc1\u4e86leader\u548cServer\u5177\u6709\u76f8\u540c\u7684\u7cfb\u7edf\u72b6\u6001\u3002<\/p>\n \u4e3a\u4e86\u4fdd\u8bc1\u4e8b\u52a1\u7684\u987a\u5e8f\u4e00\u81f4\u6027\uff0czookeeper\u91c7\u7528\u4e86\u9012\u589e\u7684\u4e8b\u52a1id\u53f7\uff08zxid\uff09\u6765\u6807\u8bc6\u4e8b\u52a1\u3002\u6240\u6709\u7684\u63d0\u8bae\uff08proposal\uff09\u90fd\u5728\u88ab\u63d0\u51fa\u7684\u65f6\u5019\u52a0\u4e0a\u4e86zxid\u3002\u5b9e\u73b0\u4e2dzxid\u662f\u4e00\u4e2a64\u4f4d\u7684\u6570\u5b57\uff0c\u5b83\u9ad832\u4f4d\u662fepoch\u7528\u6765\u6807\u8bc6leader\u5173\u7cfb\u662f\u5426\u6539\u53d8\uff0c\u6bcf\u6b21\u4e00\u4e2aleader\u88ab\u9009\u51fa\u6765\uff0c\u5b83\u90fd\u4f1a\u6709\u4e00\u4e2a\u65b0\u7684epoch\uff0c\u6807\u8bc6\u5f53\u524d\u5c5e\u4e8e\u90a3\u4e2aleader\u7684\u7edf\u6cbb\u65f6\u671f\u3002\u4f4e32\u4f4d\u7528\u4e8e\u9012\u589e\u8ba1\u6570\u3002<\/p>\n \u6bcf\u4e2aServer\u5728\u5de5\u4f5c\u8fc7\u7a0b\u4e2d\u6709\u4e09\u79cd\u72b6\u6001\uff1a<\/p>\n LOOKING\uff1a\u5f53\u524dServer\u4e0d\u77e5\u9053leader\u662f\u8c01\uff0c\u6b63\u5728\u641c\u5bfb<\/p>\n<\/li>\n LEADING\uff1a\u5f53\u524dServer\u5373\u4e3a\u9009\u4e3e\u51fa\u6765\u7684leader<\/p>\n<\/li>\n FOLLOWING\uff1aleader\u5df2\u7ecf\u9009\u4e3e\u51fa\u6765\uff0c\u5f53\u524dServer\u4e0e\u4e4b\u540c\u6b65<\/p>\n<\/li>\n<\/ul>\n \u5f53leader\u5d29\u6e83\u6216\u8005leader\u5931\u53bb\u5927\u591a\u6570\u7684follower\uff0c\u8fd9\u65f6\u5019zk\u8fdb\u5165\u6062\u590d\u6a21\u5f0f\uff0c\u6062\u590d\u6a21\u5f0f\u9700\u8981\u91cd\u65b0\u9009\u4e3e\u51fa\u4e00\u4e2a\u65b0\u7684leader\uff0c\u8ba9\u6240\u6709\u7684Server\u90fd\u6062\u590d\u5230\u4e00\u4e2a\u6b63\u786e\u7684\u72b6\u6001\u3002Zk\u7684\u9009\u4e3e\u7b97\u6cd5\u6709\u4e24\u79cd\uff1a\u4e00\u79cd\u662f\u57fa\u4e8ebasic paxos\u5b9e\u73b0\u7684\uff0c\u53e6\u5916\u4e00\u79cd\u662f\u57fa\u4e8efast paxos\u7b97\u6cd5\u5b9e\u73b0\u7684\u3002\u7cfb\u7edf\u9ed8\u8ba4\u7684\u9009\u4e3e\u7b97\u6cd5\u4e3afast paxos\u3002\u5148\u4ecb\u7ecdbasic paxos\u6d41\u7a0b\uff1a<\/p>\n 1 .\u9009\u4e3e\u7ebf\u7a0b\u7531\u5f53\u524dServer\u53d1\u8d77\u9009\u4e3e\u7684\u7ebf\u7a0b\u62c5\u4efb\uff0c\u5176\u4e3b\u8981\u529f\u80fd\u662f\u5bf9\u6295\u7968\u7ed3\u679c\u8fdb\u884c\u7edf\u8ba1\uff0c\u5e76\u9009\u51fa\u63a8\u8350\u7684Server\uff1b<\/p>\n<\/li>\n 2 .\u9009\u4e3e\u7ebf\u7a0b\u9996\u5148\u5411\u6240\u6709Server\u53d1\u8d77\u4e00\u6b21\u8be2\u95ee(\u5305\u62ec\u81ea\u5df1)\uff1b<\/p>\n<\/li>\n 3 .\u9009\u4e3e\u7ebf\u7a0b\u6536\u5230\u56de\u590d\u540e\uff0c\u9a8c\u8bc1\u662f\u5426\u662f\u81ea\u5df1\u53d1\u8d77\u7684\u8be2\u95ee(\u9a8c\u8bc1zxid\u662f\u5426\u4e00\u81f4)\uff0c\u7136\u540e\u83b7\u53d6\u5bf9\u65b9\u7684id(myid)\uff0c\u5e76\u5b58\u50a8\u5230\u5f53\u524d\u8be2\u95ee\u5bf9\u8c61\u5217\u8868\u4e2d\uff0c\u6700\u540e\u83b7\u53d6\u5bf9\u65b9\u63d0\u8bae\u7684leader\u76f8\u5173\u4fe1\u606f(id,zxid)\uff0c\u5e76\u5c06\u8fd9\u4e9b\u4fe1\u606f\u5b58\u50a8\u5230\u5f53\u6b21\u9009\u4e3e\u7684\u6295\u7968\u8bb0\u5f55\u8868\u4e2d\uff1b<\/p>\n<\/li>\n 4. \u6536\u5230\u6240\u6709Server\u56de\u590d\u4ee5\u540e\uff0c\u5c31\u8ba1\u7b97\u51fazxid\u6700\u5927\u7684\u90a3\u4e2aServer\uff0c\u5e76\u5c06\u8fd9\u4e2aServer\u76f8\u5173\u4fe1\u606f\u8bbe\u7f6e\u6210\u4e0b\u4e00\u6b21\u8981\u6295\u7968\u7684Server\uff1b<\/p>\n<\/li>\n 5. \u7ebf\u7a0b\u5c06\u5f53\u524dzxid\u6700\u5927\u7684Server\u8bbe\u7f6e\u4e3a\u5f53\u524dServer\u8981\u63a8\u8350\u7684Leader\uff0c\u5982\u679c\u6b64\u65f6\u83b7\u80dc\u7684Server\u83b7\u5f97n\/2 + 1\u7684Server\u7968\u6570\uff0c \u8bbe\u7f6e\u5f53\u524d\u63a8\u8350\u7684leader\u4e3a\u83b7\u80dc\u7684Server\uff0c\u5c06\u6839\u636e\u83b7\u80dc\u7684Server\u76f8\u5173\u4fe1\u606f\u8bbe\u7f6e\u81ea\u5df1\u7684\u72b6\u6001\uff0c\u5426\u5219\uff0c\u7ee7\u7eed\u8fd9\u4e2a\u8fc7\u7a0b\uff0c\u76f4\u5230leader\u88ab\u9009\u4e3e\u51fa\u6765\u3002<\/p>\n<\/li>\n<\/ol>\n \u901a\u8fc7\u6d41\u7a0b\u5206\u6790\u6211\u4eec\u53ef\u4ee5\u5f97\u51fa\uff1a\u8981\u4f7fLeader\u83b7\u5f97\u591a\u6570Server\u7684\u652f\u6301\uff0c\u5219Server\u603b\u6570\u5fc5\u987b\u662f\u5947\u65702n+1\uff0c\u4e14\u5b58\u6d3b\u7684Server\u7684\u6570\u76ee\u4e0d\u5f97\u5c11\u4e8en+1.<\/p>\n \u6bcf\u4e2aServer\u542f\u52a8\u540e\u90fd\u4f1a\u91cd\u590d\u4ee5\u4e0a\u6d41\u7a0b\u3002\u5728\u6062\u590d\u6a21\u5f0f\u4e0b\uff0c\u5982\u679c\u662f\u521a\u4ece\u5d29\u6e83\u72b6\u6001\u6062\u590d\u7684\u6216\u8005\u521a\u542f\u52a8\u7684server\u8fd8\u4f1a\u4ece\u78c1\u76d8\u5feb\u7167\u4e2d\u6062\u590d\u6570\u636e\u548c\u4f1a\u8bdd\u4fe1\u606f\uff0czk\u4f1a\u8bb0\u5f55\u4e8b\u52a1\u65e5\u5fd7\u5e76\u5b9a\u671f\u8fdb\u884c\u5feb\u7167\uff0c\u65b9\u4fbf\u5728\u6062\u590d\u65f6\u8fdb\u884c\u72b6\u6001\u6062\u590d\u3002\u9009\u4e3b\u7684\u5177\u4f53\u6d41\u7a0b\u56fe\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n fast paxos\u6d41\u7a0b\u662f\u5728\u9009\u4e3e\u8fc7\u7a0b\u4e2d\uff0c\u67d0Server\u9996\u5148\u5411\u6240\u6709Server\u63d0\u8bae\u81ea\u5df1\u8981\u6210\u4e3aleader\uff0c\u5f53\u5176\u5b83Server\u6536\u5230\u63d0\u8bae\u4ee5\u540e\uff0c\u89e3\u51b3epoch\u548czxid\u7684\u51b2\u7a81\uff0c\u5e76\u63a5\u53d7\u5bf9\u65b9\u7684\u63d0\u8bae\uff0c\u7136\u540e\u5411\u5bf9\u65b9\u53d1\u9001\u63a5\u53d7\u63d0\u8bae\u5b8c\u6210\u7684\u6d88\u606f\uff0c\u91cd\u590d\u8fd9\u4e2a\u6d41\u7a0b\uff0c\u6700\u540e\u4e00\u5b9a\u80fd\u9009\u4e3e\u51faLeader\u3002\u5176\u6d41\u7a0b\u56fe\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n <\/a> \u9009\u5b8cleader\u4ee5\u540e\uff0czk\u5c31\u8fdb\u5165\u72b6\u6001\u540c\u6b65\u8fc7\u7a0b\u3002<\/p>\n 1. leader\u7b49\u5f85server\u8fde\u63a5\uff1b<\/p>\n<\/li>\n 2 .Follower\u8fde\u63a5leader\uff0c\u5c06\u6700\u5927\u7684zxid\u53d1\u9001\u7ed9leader\uff1b<\/p>\n<\/li>\n 3 .Leader\u6839\u636efollower\u7684zxid\u786e\u5b9a\u540c\u6b65\u70b9\uff1b<\/p>\n<\/li>\n 4 .\u5b8c\u6210\u540c\u6b65\u540e\u901a\u77e5follower \u5df2\u7ecf\u6210\u4e3auptodate\u72b6\u6001\uff1b<\/p>\n<\/li>\n 5 .Follower\u6536\u5230uptodate\u6d88\u606f\u540e\uff0c\u53c8\u53ef\u4ee5\u91cd\u65b0\u63a5\u53d7client\u7684\u8bf7\u6c42\u8fdb\u884c\u670d\u52a1\u4e86\u3002<\/p>\n<\/li>\n<\/ol>\n \u6d41\u7a0b\u56fe\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n Leader\u4e3b\u8981\u6709\u4e09\u4e2a\u529f\u80fd\uff1a<\/p>\n 1 .\u6062\u590d\u6570\u636e\uff1b<\/p>\n<\/li>\n 2 .\u7ef4\u6301\u4e0eLearner\u7684\u5fc3\u8df3\uff0c\u63a5\u6536Learner\u8bf7\u6c42\u5e76\u5224\u65adLearner\u7684\u8bf7\u6c42\u6d88\u606f\u7c7b\u578b\uff1b<\/p>\n<\/li>\n 3 .Learner\u7684\u6d88\u606f\u7c7b\u578b\u4e3b\u8981\u6709PING\u6d88\u606f\u3001REQUEST\u6d88\u606f\u3001ACK\u6d88\u606f\u3001REVALIDATE\u6d88\u606f\uff0c\u6839\u636e\u4e0d\u540c\u7684\u6d88\u606f\u7c7b\u578b\uff0c\u8fdb\u884c\u4e0d\u540c\u7684\u5904\u7406\u3002<\/p>\n<\/li>\n<\/ol>\n PING\u6d88\u606f\u662f\u6307Learner\u7684\u5fc3\u8df3\u4fe1\u606f\uff1bREQUEST\u6d88\u606f\u662fFollower\u53d1\u9001\u7684\u63d0\u8bae\u4fe1\u606f\uff0c\u5305\u62ec\u5199\u8bf7\u6c42\u53ca\u540c\u6b65\u8bf7\u6c42\uff1bACK\u6d88\u606f\u662fFollower\u7684\u5bf9\u63d0\u8bae\u7684\u56de\u590d\uff0c\u8d85\u8fc7\u534a\u6570\u7684Follower\u901a\u8fc7\uff0c\u5219commit\u8be5\u63d0\u8bae\uff1bREVALIDATE\u6d88\u606f\u662f\u7528\u6765\u5ef6\u957fSESSION\u6709\u6548\u65f6\u95f4\u3002 Follower\u4e3b\u8981\u6709\u56db\u4e2a\u529f\u80fd\uff1a<\/p>\n 1. \u5411Leader\u53d1\u9001\u8bf7\u6c42\uff08PING\u6d88\u606f\u3001REQUEST\u6d88\u606f\u3001ACK\u6d88\u606f\u3001REVALIDATE\u6d88\u606f\uff09\uff1b<\/p>\n<\/li>\n 2 .\u63a5\u6536Leader\u6d88\u606f\u5e76\u8fdb\u884c\u5904\u7406\uff1b<\/p>\n<\/li>\n 3 .\u63a5\u6536Client\u7684\u8bf7\u6c42\uff0c\u5982\u679c\u4e3a\u5199\u8bf7\u6c42\uff0c\u53d1\u9001\u7ed9Leader\u8fdb\u884c\u6295\u7968\uff1b<\/p>\n<\/li>\n 4 .\u8fd4\u56deClient\u7ed3\u679c\u3002<\/p>\n<\/li>\n<\/ol>\n Follower\u7684\u6d88\u606f\u5faa\u73af\u5904\u7406\u5982\u4e0b\u51e0\u79cd\u6765\u81eaLeader\u7684\u6d88\u606f\uff1a<\/p>\n 1 .PING<\/span>\u6d88\u606f\uff1a \u5fc3\u8df3\u6d88\u606f\uff1b<\/p>\n<\/li>\n 2 .PROPOSAL<\/span>\u6d88\u606f\uff1aLeader\u53d1\u8d77\u7684\u63d0\u6848\uff0c\u8981\u6c42Follower\u6295\u7968\uff1b<\/p>\n<\/li>\n 3 .COMMIT<\/span>\u6d88\u606f\uff1a\u670d\u52a1\u5668\u7aef\u6700\u65b0\u4e00\u6b21\u63d0\u6848\u7684\u4fe1\u606f\uff1b<\/p>\n<\/li>\n 4 .UPTODATE<\/span>\u6d88\u606f\uff1a\u8868\u660e\u540c\u6b65\u5b8c\u6210\uff1b<\/p>\n<\/li>\n 5 .REVALIDATE<\/span>\u6d88\u606f\uff1a\u6839\u636eLeader\u7684REVALIDATE\u7ed3\u679c\uff0c\u5173\u95ed\u5f85revalidate\u7684session\u8fd8\u662f\u5141\u8bb8\u5176\u63a5\u53d7\u6d88\u606f\uff1b<\/p>\n<\/li>\n 6 .SYNC<\/span>\u6d88\u606f\uff1a\u8fd4\u56deSYNC\u7ed3\u679c\u5230\u5ba2\u6237\u7aef\uff0c\u8fd9\u4e2a\u6d88\u606f\u6700\u521d\u7531\u5ba2\u6237\u7aef\u53d1\u8d77\uff0c\u7528\u6765\u5f3a\u5236\u5f97\u5230\u6700\u65b0\u7684\u66f4\u65b0\u3002<\/p>\n<\/li>\n<\/ol>\n Follower\u7684\u5de5\u4f5c\u6d41\u7a0b\u7b80\u56fe\u5982\u4e0b\u6240\u793a\uff0c\u5728\u5b9e\u9645\u5b9e\u73b0\u4e2d\uff0cFollower\u662f\u901a\u8fc75\u4e2a\u7ebf\u7a0b\u6765\u5b9e\u73b0\u529f\u80fd\u7684\u3002<\/p>\n \u5bf9\u4e8eobserver\u7684\u6d41\u7a0b\u4e0d\u518d\u53d9\u8ff0\uff0cobserver\u6d41\u7a0b\u548cFollower\u7684\u552f\u4e00\u4e0d\u540c\u7684\u5730\u65b9\u5c31\u662fobserver\u4e0d\u4f1a\u53c2\u52a0leader\u53d1\u8d77\u7684\u6295\u7968\u3002<\/p>\n Zookeeper<\/span>\u7684\u4e3b\u6d41\u5e94\u7528\u573a\u666f\u5b9e\u73b0\u601d\u8def\uff08\u9664\u53bb\u5b98\u65b9\u793a\u4f8b\uff09<\/span><\/span><\/span> Zookeeper C API \u7684\u58f0\u660e\u548c\u63cf\u8ff0\u5728 include\/zookeeper.h \u4e2d\u53ef\u4ee5\u627e\u5230\uff0c\u53e6\u5916\u5927\u90e8\u5206\u7684 Zookeeper C API \u5e38\u91cf\u3001\u7ed3\u6784\u4f53\u58f0\u660e\u4e5f\u5728 zookeeper.h \u4e2d\uff0c\u5982\u679c\u5982\u679c\u4f60\u5728\u4f7f\u7528 C API \u662f\u9047\u5230\u4e0d\u660e\u767d\u7684\u5730\u65b9\uff0c\u6700\u597d\u770b\u770b zookeeper.h\uff0c\u6216\u8005\u81ea\u5df1\u4f7f\u7528 doxygen \u751f\u6210 Zookeeper C API \u7684\u5e2e\u52a9\u6587\u6863\u3002<\/p>\n Zookeeper \u4e2d\u6700\u6709\u7279\u8272\u4e14\u6700\u4e0d\u5bb9\u6613\u7406\u89e3\u7684\u662f\u76d1\u89c6(Watches)\u3002Zookeeper \u6240\u6709\u7684\u8bfb\u64cd\u4f5c\u2014\u2014getData()<\/span>, getChildren()<\/span>, \u548c exists() <\/span>\u90fd \u53ef\u4ee5\u8bbe\u7f6e\u76d1\u89c6(watch)\uff0c\u76d1\u89c6\u4e8b\u4ef6\u53ef\u4ee5\u7406\u89e3\u4e3a\u4e00\u6b21\u6027\u7684\u89e6\u53d1\u5668\uff0c \u5b98\u65b9\u5b9a\u4e49\u5982\u4e0b\uff1a a watch event is one-time trigger, sent to the client that set the watch, which occurs when the data for which the watch was set changes\u3002\u5bf9\u6b64\u9700\u8981\u4f5c\u51fa\u5982\u4e0b\u7406\u89e3\uff1a<\/p>\n \uff08\u4e00\u6b21\u6027\u89e6\u53d1\uff09One-time trigger<\/span><\/p>\n \u5f53\u8bbe\u7f6e\u76d1\u89c6\u7684\u6570\u636e\u53d1\u751f\u6539\u53d8\u65f6\uff0c\u8be5\u76d1\u89c6\u4e8b\u4ef6\u4f1a\u88ab\u53d1\u9001\u5230\u5ba2\u6237\u7aef\uff0c\u4f8b\u5982\uff0c\u5982\u679c\u5ba2\u6237\u7aef\u8c03\u7528\u4e86 getData(\"\/znode1\", true) \u5e76\u4e14\u7a0d\u540e \/znode1 \u8282\u70b9\u4e0a\u7684\u6570\u636e\u53d1\u751f\u4e86\u6539\u53d8\u6216\u8005\u88ab\u5220\u9664\u4e86\uff0c\u5ba2\u6237\u7aef\u5c06\u4f1a\u83b7\u53d6\u5230 \/znode1 \u53d1\u751f\u53d8\u5316\u7684\u76d1\u89c6\u4e8b\u4ef6\uff0c\u800c\u5982\u679c \/znode1 \u518d\u4e00\u6b21\u53d1\u751f\u4e86\u53d8\u5316\uff0c\u9664\u975e\u5ba2\u6237\u7aef\u518d\u6b21\u5bf9 \/znode1 \u8bbe\u7f6e\u76d1\u89c6\uff0c\u5426\u5219\u5ba2\u6237\u7aef\u4e0d\u4f1a\u6536\u5230\u4e8b\u4ef6\u901a\u77e5\u3002<\/p>\n<\/li>\n \uff08\u53d1\u9001\u81f3\u5ba2\u6237\u7aef\uff09Sent to the client<\/span><\/p>\n Zookeeper \u5ba2\u6237\u7aef\u548c\u670d\u52a1\u7aef\u662f\u901a\u8fc7 socket \u8fdb\u884c\u901a\u4fe1\u7684\uff0c\u7531\u4e8e\u7f51\u7edc\u5b58\u5728\u6545\u969c\uff0c\u6240\u4ee5\u76d1\u89c6\u4e8b\u4ef6\u5f88\u6709\u53ef\u80fd\u4e0d\u4f1a\u6210\u529f\u5730\u5230\u8fbe\u5ba2\u6237\u7aef\uff0c\u76d1\u89c6\u4e8b\u4ef6\u662f\u5f02\u6b65\u53d1\u9001\u81f3\u76d1\u89c6\u8005\u7684\uff0cZookeeper \u672c\u8eab\u63d0\u4f9b\u4e86\u4fdd\u5e8f\u6027(ordering guarantee)\uff1a\u5373\u5ba2\u6237\u7aef\u53ea\u6709\u9996\u5148\u770b\u5230\u4e86\u76d1\u89c6\u4e8b\u4ef6\u540e\uff0c\u624d\u4f1a\u611f\u77e5\u5230\u5b83\u6240\u8bbe\u7f6e\u76d1\u89c6\u7684 znode \u53d1\u751f\u4e86\u53d8\u5316(a client will never see a change for which it has set a watch until it first sees the watch event). \u7f51\u7edc\u5ef6\u8fdf\u6216\u8005\u5176\u4ed6\u56e0\u7d20\u53ef\u80fd\u5bfc\u81f4\u4e0d\u540c\u7684\u5ba2\u6237\u7aef\u5728\u4e0d\u540c\u7684\u65f6\u523b\u611f\u77e5\u67d0\u4e00\u76d1\u89c6\u4e8b\u4ef6\uff0c\u4f46\u662f\u4e0d\u540c\u7684\u5ba2\u6237\u7aef\u6240\u770b\u5230\u7684\u4e00\u5207\u5177\u6709\u4e00\u81f4\u7684\u987a\u5e8f\u3002<\/span><\/p>\n<\/li>\n \uff08\u88ab\u8bbe\u7f6e w<\/span>atch \u7684\u6570\u636e\uff09The data for which the watch was set<\/span><\/p>\n \u8fd9\u610f\u5473\u7740 znode \u8282\u70b9\u672c\u8eab\u5177\u6709\u4e0d\u540c\u7684\u6539\u53d8\u65b9\u5f0f\u3002\u4f60\u4e5f\u53ef\u4ee5\u60f3\u8c61 Zookeeper \u7ef4\u62a4\u4e86\u4e24\u6761\u76d1\u89c6\u94fe\u8868\uff1a\u6570\u636e\u76d1\u89c6\u548c\u5b50\u8282\u70b9\u76d1\u89c6(data watches and child watches) getData() and exists() \u8bbe\u7f6e\u6570\u636e\u76d1\u89c6\uff0cgetChildren() \u8bbe\u7f6e\u5b50\u8282\u70b9\u76d1\u89c6\u3002 \u6216\u8005\uff0c\u4f60\u4e5f\u53ef\u4ee5\u60f3\u8c61 Zookeeper \u8bbe\u7f6e\u7684\u4e0d\u540c\u76d1\u89c6\u8fd4\u56de\u4e0d\u540c\u7684\u6570\u636e\uff0cgetData() \u548c exists() \u8fd4\u56de znode \u8282\u70b9\u7684\u76f8\u5173\u4fe1\u606f\uff0c\u800c getChildren() \u8fd4\u56de\u5b50\u8282\u70b9\u5217\u8868\u3002\u56e0\u6b64\uff0c setData() \u4f1a\u89e6\u53d1\u8bbe\u7f6e\u5728\u67d0\u4e00\u8282\u70b9\u4e0a\u6240\u8bbe\u7f6e\u7684\u6570\u636e\u76d1\u89c6(\u5047\u5b9a\u6570\u636e\u8bbe\u7f6e\u6210\u529f)\uff0c\u800c\u4e00\u6b21\u6210\u529f\u7684 create() \u64cd\u4f5c\u5219\u4f1a\u51fa\u53d1\u5f53\u524d\u8282\u70b9\u4e0a\u6240\u8bbe\u7f6e\u7684\u6570\u636e\u76d1\u89c6\u4ee5\u53ca\u7236\u8282\u70b9\u7684\u5b50\u8282\u70b9\u76d1\u89c6\u3002\u4e00\u6b21\u6210\u529f\u7684 delete() \u64cd\u4f5c\u5c06\u4f1a\u89e6\u53d1\u5f53\u524d\u8282\u70b9\u7684\u6570\u636e\u76d1\u89c6\u548c\u5b50\u8282\u70b9\u76d1\u89c6\u4e8b\u4ef6\uff0c\u540c\u65f6\u4e5f\u4f1a\u89e6\u53d1\u8be5\u8282\u70b9\u7236\u8282\u70b9\u7684child watch\u3002<\/p>\n<\/li>\n<\/ul>\n Zookeeper \u4e2d\u7684\u76d1\u89c6\u662f\u8f7b\u91cf\u7ea7\u7684\uff0c\u56e0\u6b64\u5bb9\u6613\u8bbe\u7f6e\u3001\u7ef4\u62a4\u548c\u5206\u53d1\u3002\u5f53\u5ba2\u6237\u7aef\u4e0e Zookeeper \u670d\u52a1\u5668\u7aef\u5931\u53bb\u8054\u7cfb\u65f6\uff0c\u5ba2\u6237\u7aef\u5e76\u4e0d\u4f1a\u6536\u5230\u76d1\u89c6\u4e8b\u4ef6\u7684\u901a\u77e5\uff0c\u53ea\u6709\u5f53\u5ba2\u6237\u7aef\u91cd\u65b0\u8fde\u63a5\u540e\uff0c\u82e5\u5728\u5fc5\u8981\u7684\u60c5\u51b5\u4e0b\uff0c\u4ee5\u524d\u6ce8\u518c\u7684\u76d1\u89c6\u4f1a\u91cd\u65b0\u88ab\u6ce8\u518c\u5e76\u89e6\u53d1\uff0c\u5bf9\u4e8e\u5f00\u53d1\u4eba\u5458\u6765\u8bf4 \u8fd9\u901a\u5e38\u662f\u900f\u660e\u7684\u3002\u53ea\u6709\u4e00\u79cd\u60c5\u51b5\u4f1a\u5bfc\u81f4\u76d1\u89c6\u4e8b\u4ef6\u7684\u4e22\u5931\uff0c\u5373\uff1a\u901a\u8fc7 exists() \u8bbe\u7f6e\u4e86\u67d0\u4e2a znode \u8282\u70b9\u7684\u76d1\u89c6\uff0c\u4f46\u662f\u5982\u679c\u67d0\u4e2a\u5ba2\u6237\u7aef\u5728\u6b64 znode \u8282\u70b9\u88ab\u521b\u5efa\u548c\u5220\u9664\u7684\u65f6\u95f4\u95f4\u9694\u5185\u4e0e zookeeper \u670d\u52a1\u5668\u5931\u53bb\u4e86\u8054\u7cfb\uff0c\u8be5\u5ba2\u6237\u7aef\u5373\u4f7f\u7a0d\u540e\u91cd\u65b0\u8fde\u63a5 zookeeper\u670d\u52a1\u5668\u540e\u4e5f\u5f97\u4e0d\u5230\u4e8b\u4ef6\u901a\u77e5\u3002<\/p>\n struct Id \u7ed3\u6784\u4e3a\uff1a<\/p>\n <\/p>\n struct ACL \u7ed3\u6784\u4e3a\uff1a<\/p>\n <\/p>\n struct ACL_vector \u7ed3\u6784\u4e3a\uff1a<\/p>\n <\/p>\n \u4e0e znode \u8bbf\u95ee\u6743\u9650\u6709\u5173\u7684\u5e38\u91cf<\/p>\n const<\/span> int<\/span> ZOO_PERM_READ; \/\/\u5141\u8bb8\u5ba2\u6237\u7aef\u8bfb\u53d6 znode \u8282\u70b9\u7684\u503c\u4ee5\u53ca\u5b50\u8282\u70b9\u5217\u8868\u3002<\/p>\n<\/li>\n const<\/span> int<\/span> ZOO_PERM_WRITE;\/\/ \u5141\u8bb8\u5ba2\u6237\u7aef\u8bbe\u7f6e znode \u8282\u70b9\u7684\u503c\u3002<\/p>\n<\/li>\n const<\/span> int<\/span> ZOO_PERM_CREATE; \/\/\u5141\u8bb8\u5ba2\u6237\u7aef\u5728\u8be5 znode \u8282\u70b9\u4e0b\u521b\u5efa\u5b50\u8282\u70b9\u3002<\/p>\n<\/li>\n const<\/span> int<\/span> ZOO_PERM_DELETE;\/\/\u5141\u8bb8\u5ba2\u6237\u7aef\u5220\u9664\u5b50\u8282\u70b9\u3002<\/p>\n<\/li>\n const<\/span> int<\/span> ZOO_PERM_ADMIN; \/\/\u5141\u8bb8\u5ba2\u6237\u7aef\u6267\u884c set_acl()\u3002<\/p>\n<\/li>\n const<\/span> int<\/span> ZOO_PERM_ALL;\/\/\u5141\u8bb8\u5ba2\u6237\u7aef\u6267\u884c\u6240\u6709\u64cd\u4f5c\uff0c\u7b49\u4ef7\u4e0e\u4e0a\u8ff0\u6240\u6709\u6807\u5fd7\u7684\u6216(OR) \u3002<\/p>\n<\/li>\n<\/ul>\n \u4e0e ACL IDs \u76f8\u5173\u7684\u5e38\u91cf<\/p>\n struct<\/span> Id ZOO_ANYONE_ID_UNSAFE; \/\/(\u2018world\u2019,\u2019anyone\u2019)<\/p>\n<\/li>\n struct<\/span> Id ZOO_AUTH_IDS;\/\/ (\u2018auth\u2019,\u2019\u2019)<\/p>\n<\/li>\n<\/ul>\n \u4e09\u79cd\u6807\u51c6\u7684 ACL<\/p>\n struct<\/span> ACL_vector ZOO_OPEN_ACL_UNSAFE; \/\/(ZOO_PERM_ALL,ZOO_ANYONE_ID_UNSAFE)<\/p>\n<\/li>\n struct<\/span> ACL_vector ZOO_READ_ACL_UNSAFE;\/\/ (ZOO_PERM_READ, ZOO_ANYONE_ID_UNSAFE)<\/p>\n<\/li>\n struct<\/span> ACL_vector ZOO_CREATOR_ALL_ACL; \/\/(ZOO_PERM_ALL,ZOO_AUTH_IDS)<\/p>\n<\/li>\n<\/ul>\n \u8fd9 \u4e24\u4e2a\u5e38\u91cf\u7528\u4e8e\u6807\u8bc6\u611f\u5174\u8da3\u7684\u4e8b\u4ef6\u5e76\u901a\u77e5 zookeeper \u53d1\u751f\u4e86\u54ea\u4e9b\u4e8b\u4ef6\u3002Interest \u5e38\u91cf\u53ef\u4ee5\u8fdb\u884c\u7ec4\u5408\u6216\uff08OR\uff09\u6765\u6807\u8bc6\u591a\u79cd\u5174\u8da3(multiple interests: write, read)\uff0c\u8fd9\u4e24\u4e2a\u5e38\u91cf\u4e00\u822c\u7528\u4e8e zookeeper_interest() \u548c zookeeper_process()\u4e24\u4e2a\u51fd\u6570\u4e2d\u3002<\/p>\n zoo_create \u51fd\u6570\u6807\u5fd7\uff0cZOO_EPHEMERAL<\/span> \u7528\u6765\u6807\u8bc6\u521b\u5efa\u4e34\u65f6\u8282\u70b9\uff0cZOO_SEQUENCE<\/span> \u7528\u6765\u6807\u8bc6\u8282\u70b9\u547d\u540d\u5177\u6709\u9012\u589e\u7684\u540e\u7f00\u5e8f\u53f7(\u4e00\u822c\u662f\u8282\u70b9\u540d\u79f0\u540e\u586b\u5145 10 \u4f4d\u5b57\u7b26\u7684\u5e8f\u53f7\uff0c\u5982 \/xyz0000000000, \/xyz0000000001, \/xyz0000000002, ...)\uff0c\u540c\u6837\u5730\uff0cZOO_EPHEMERAL<\/span>, ZOO_SEQUENCE <\/span>\u53ef\u4ee5\u7ec4\u5408\u3002<\/p>\n \u4ee5\u4e0b\u5e38\u91cf\u5747\u4e0e Zookeeper \u8fde\u63a5\u72b6\u6001\u6709\u5173\uff0c\u4ed6\u4eec\u901a\u5e38\u7528\u4f5c\u76d1\u89c6\u5668\u56de\u8c03\u51fd\u6570\u7684\u53c2\u6570\u3002<\/p>\n![\"\u70b9\u51fb\u67e5\u770b\u539f\u56fe\"](\"http:\/\/static.oschina.net\/uploads\/img\/201308\/08171344_cqXs.jpg\")
<\/a><\/a><\/p>\n1.2 \u8bbe\u8ba1\u76ee\u7684<\/h2>\n
2 ZooKeeper\u7684\u5de5\u4f5c\u539f\u7406<\/h1>\n
\n
2.1 \u9009\u4e3b\u6d41\u7a0b<\/h2>\n
\n
<\/a><\/a><\/p>\n<\/a><\/p>\n2.2 \u540c\u6b65\u6d41\u7a0b<\/h2>\n
\n
<\/a><\/a><\/p>\n2.3 \u5de5\u4f5c\u6d41\u7a0b<\/h2>\n
2.3.1 Leader\u5de5\u4f5c\u6d41\u7a0b<\/h3>\n
\n
\nLeader\u7684\u5de5\u4f5c\u6d41\u7a0b\u7b80\u56fe\u5982\u4e0b\u6240\u793a\uff0c\u5728\u5b9e\u9645\u5b9e\u73b0\u4e2d\uff0c\u6d41\u7a0b\u8981\u6bd4\u4e0b\u56fe\u590d\u6742\u5f97\u591a\uff0c\u542f\u52a8\u4e86\u4e09\u4e2a\u7ebf\u7a0b\u6765\u5b9e\u73b0\u529f\u80fd\u3002<\/a><\/a><\/p>\n2.3.2 Follower\u5de5\u4f5c\u6d41\u7a0b<\/h3>\n
\n
\n
<\/a><\/a><\/p>\n
\n\u4e3b\u6d41\u5e94\u7528\u573a\u666f\uff1a<\/p>\n
\n<\/span>
\n(1)<\/span><\/span>\u914d\u7f6e\u7ba1\u7406
\n<\/span><\/span><\/span>\u96c6\u4e2d\u5f0f\u7684\u914d\u7f6e\u7ba1\u7406\u5728\u5e94\u7528\u96c6\u7fa4\u4e2d\u662f\u975e\u5e38\u5e38\u89c1\u7684\uff0c\u4e00\u822c\u5546\u4e1a\u516c\u53f8\u5185\u90e8\u90fd\u4f1a\u5b9e\u73b0\u4e00\u5957\u96c6\u4e2d\u7684\u914d\u7f6e\u7ba1\u7406\u4e2d\u5fc3\uff0c\u5e94\u5bf9\u4e0d\u540c\u7684\u5e94\u7528\u96c6\u7fa4\u5bf9\u4e8e\u5171\u4eab\u5404\u81ea\u914d\u7f6e\u7684\u9700\u6c42\uff0c\u5e76\u4e14\u5728\u914d\u7f6e\u53d8\u66f4\u65f6\u80fd\u591f\u901a\u77e5\u5230\u96c6\u7fa4\u4e2d\u7684\u6bcf\u4e00\u4e2a\u673a\u5668\u3002
\n<\/span><\/span>
\nZookeeper<\/span>\u5f88\u5bb9\u6613\u5b9e\u73b0\u8fd9\u79cd\u96c6\u4e2d\u5f0f\u7684\u914d\u7f6e\u7ba1\u7406\uff0c\u6bd4\u5982\u5c06<\/span>APP1<\/span>\u7684\u6240\u6709\u914d\u7f6e\u914d\u7f6e\u5230<\/span>\/APP1 znode<\/span>\u4e0b\uff0c<\/span>APP1<\/span>\u6240\u6709\u673a\u5668\u4e00\u542f\u52a8\u5c31\u5bf9<\/span>\/APP1<\/span>\u8fd9\u4e2a\u8282\u70b9\u8fdb\u884c\u76d1\u63a7<\/span>(zk.exist(<\/span>\"\/APP1\"<\/span>,true)),<\/span>\u5e76\u4e14\u5b9e\u73b0\u56de\u8c03\u65b9\u6cd5<\/span>Watcher<\/span>\uff0c\u90a3\u4e48\u5728<\/span>zookeeper<\/span>\u4e0a<\/span>\/APP1 znode<\/span>\u8282\u70b9\u4e0b\u6570\u636e\u53d1\u751f\u53d8\u5316\u7684\u65f6\u5019\uff0c\u6bcf\u4e2a\u673a\u5668\u90fd\u4f1a\u6536\u5230\u901a\u77e5\uff0c<\/span>Watcher<\/span>\u65b9\u6cd5\u5c06\u4f1a\u88ab\u6267\u884c\uff0c\u90a3\u4e48\u5e94\u7528\u518d\u53d6\u4e0b\u6570\u636e\u5373\u53ef<\/span>(zk.getData(<\/span>\"\/APP1\",false,null<\/span>));
\n<\/span><\/span>
\n\u4ee5\u4e0a\u8fd9\u4e2a\u4f8b\u5b50\u53ea\u662f\u7b80\u5355\u7684\u7c97\u9897\u7c92\u5ea6\u914d\u7f6e\u76d1\u63a7\uff0c\u7ec6\u9897\u7c92\u5ea6\u7684\u6570\u636e\u53ef\u4ee5\u8fdb\u884c\u5206\u5c42\u7ea7\u76d1\u63a7\uff0c\u8fd9\u4e00\u5207\u90fd\u662f\u53ef\u4ee5\u8bbe\u8ba1\u548c\u63a7\u5236\u7684\u3002<\/span><\/span> <\/a><\/a>
\n(2)<\/span>\u96c6\u7fa4\u7ba1\u7406<\/span><\/span>
\n<\/span>\u5e94\u7528\u96c6\u7fa4\u4e2d\uff0c\u6211\u4eec\u5e38\u5e38\u9700\u8981\u8ba9\u6bcf\u4e00\u4e2a\u673a\u5668\u77e5\u9053\u96c6\u7fa4\u4e2d\uff08\u6216\u4f9d\u8d56\u7684\u5176\u4ed6\u67d0\u4e00\u4e2a\u96c6\u7fa4\uff09\u54ea\u4e9b\u673a\u5668\u662f\u6d3b\u7740\u7684\uff0c\u5e76\u4e14\u5728\u96c6\u7fa4\u673a\u5668\u56e0\u4e3a\u5b95\u673a\uff0c\u7f51\u7edc\u65ad\u94fe\u7b49\u539f\u56e0\u80fd\u591f\u4e0d\u5728\u4eba\u5de5\u4ecb\u5165\u7684\u60c5\u51b5\u4e0b\u8fc5\u901f\u901a\u77e5\u5230\u6bcf\u4e00\u4e2a\u673a\u5668\u3002
\n<\/span><\/span>
\nZookeeper<\/span>\u540c\u6837\u5f88\u5bb9\u6613\u5b9e\u73b0\u8fd9\u4e2a\u529f\u80fd\uff0c\u6bd4\u5982\u6211\u5728<\/span>zookeeper<\/span>\u670d\u52a1\u5668\u7aef\u6709\u4e00\u4e2a<\/span>znode<\/span>\u53eb<\/span>\/APP1SERVERS,<\/span>\u90a3\u4e48\u96c6\u7fa4\u4e2d\u6bcf\u4e00\u4e2a\u673a\u5668\u542f\u52a8\u7684\u65f6\u5019\u90fd\u53bb\u8fd9\u4e2a\u8282\u70b9\u4e0b\u521b\u5efa\u4e00\u4e2a<\/span>EPHEMERAL<\/span>\u7c7b\u578b\u7684\u8282\u70b9\uff0c\u6bd4\u5982<\/span>server1<\/span>\u521b\u5efa<\/span>\/APP1SERVERS\/SERVER1(<\/span>\u53ef\u4ee5\u4f7f\u7528<\/span>ip,<\/span>\u4fdd\u8bc1\u4e0d\u91cd\u590d<\/span>)<\/span>\uff0c<\/span>server2<\/span>\u521b\u5efa<\/span>\/APP1SERVERS\/SERVER2<\/span>\uff0c\u7136\u540e<\/span>SERVER1<\/span>\u548c<\/span>SERVER2<\/span>\u90fd<\/span>watch \/APP1SERVERS<\/span>\u8fd9\u4e2a\u7236\u8282\u70b9\uff0c\u90a3\u4e48\u4e5f\u5c31\u662f\u8fd9\u4e2a\u7236\u8282\u70b9\u4e0b\u6570\u636e\u6216\u8005\u5b50\u8282\u70b9\u53d8\u5316\u90fd\u4f1a\u901a\u77e5\u5bf9\u8be5\u8282\u70b9\u8fdb\u884c<\/span>watch<\/span>\u7684\u5ba2\u6237\u7aef\u3002\u56e0\u4e3a<\/span>EPHEMERAL<\/span>\u7c7b\u578b\u8282\u70b9\u6709\u4e00\u4e2a\u5f88\u91cd\u8981\u7684\u7279\u6027\uff0c\u5c31\u662f\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u7aef\u8fde\u63a5\u65ad\u6389\u6216\u8005<\/span>session<\/span>\u8fc7\u671f\u5c31\u4f1a\u4f7f\u8282\u70b9\u6d88\u5931\uff0c\u90a3\u4e48\u5728\u67d0\u4e00\u4e2a\u673a\u5668\u6302\u6389\u6216\u8005\u65ad\u94fe\u7684\u65f6\u5019\uff0c\u5176\u5bf9\u5e94\u7684\u8282\u70b9\u5c31\u4f1a\u6d88\u5931\uff0c\u7136\u540e\u96c6\u7fa4\u4e2d\u6240\u6709\u5bf9<\/span>\/APP1SERVERS<\/span>\u8fdb\u884c<\/span>watch<\/span>\u7684\u5ba2\u6237\u7aef\u90fd\u4f1a\u6536\u5230\u901a\u77e5\uff0c\u7136\u540e\u53d6\u5f97\u6700\u65b0\u5217\u8868\u5373\u53ef\u3002
\n<\/span><\/span>
\n\u53e6\u5916\u6709\u4e00\u4e2a\u5e94\u7528\u573a\u666f\u5c31\u662f\u96c6\u7fa4\u9009<\/span>master,<\/span>\u4e00\u65e6<\/span>master<\/span>\u6302\u6389\u80fd\u591f\u9a6c\u4e0a\u80fd\u4ece<\/span>slave<\/span>\u4e2d\u9009\u51fa\u4e00\u4e2a<\/span>master,<\/span>\u5b9e\u73b0\u6b65\u9aa4\u548c\u524d\u8005\u4e00\u6837\uff0c\u53ea\u662f\u673a\u5668\u5728\u542f\u52a8\u7684\u65f6\u5019\u5728<\/span>APP1SERVERS<\/span>\u521b\u5efa\u7684\u8282\u70b9\u7c7b\u578b\u53d8\u4e3a<\/span>EPHEMERAL_SEQUENTIAL<\/span>\u7c7b\u578b\uff0c\u8fd9\u6837\u6bcf\u4e2a\u8282\u70b9\u4f1a\u81ea\u52a8\u88ab\u7f16\u53f7
\n<\/span><\/span><\/span>
\n\u6211\u4eec\u9ed8\u8ba4\u89c4\u5b9a\u7f16\u53f7\u6700\u5c0f\u7684\u4e3a<\/span>master,<\/span>\u6240\u4ee5\u5f53\u6211\u4eec\u5bf9<\/span>\/APP1SERVERS<\/span>\u8282\u70b9\u505a\u76d1\u63a7\u7684\u65f6\u5019\uff0c\u5f97\u5230\u670d\u52a1\u5668\u5217\u8868\uff0c\u53ea\u8981\u6240\u6709\u96c6\u7fa4\u673a\u5668\u903b\u8f91\u8ba4\u4e3a\u6700\u5c0f\u7f16\u53f7\u8282\u70b9\u4e3a<\/span>master<\/span>\uff0c\u90a3\u4e48<\/span>master<\/span>\u5c31\u88ab\u9009\u51fa\uff0c\u800c\u8fd9\u4e2a<\/span>master<\/span>\u5b95\u673a\u7684\u65f6\u5019\uff0c\u76f8\u5e94\u7684<\/span>znode<\/span>\u4f1a\u6d88\u5931\uff0c\u7136\u540e\u65b0\u7684\u670d\u52a1\u5668\u5217\u8868\u5c31\u88ab\u63a8\u9001\u5230\u5ba2\u6237\u7aef\uff0c\u7136\u540e\u6bcf\u4e2a\u8282\u70b9\u903b\u8f91\u8ba4\u4e3a\u6700\u5c0f\u7f16\u53f7\u8282\u70b9\u4e3a<\/span>master<\/span>\uff0c\u8fd9\u6837\u5c31\u505a\u5230\u52a8\u6001<\/span>master<\/span>\u9009\u4e3e\u3002
\n<\/span><\/a><\/a>
\n<\/span><\/p>\nZookeeper \u76d1\u89c6\uff08Watches\uff09 \u7b80\u4ecb<\/span><\/h3>\n
\n
Zookeeper C API \u5e38\u91cf\u4e0e\u90e8\u5206\u7ed3\u6784(struct)\u4ecb\u7ecd<\/h3>\n
\u4e0e ACL \u76f8\u5173\u7684\u7ed3\u6784\u4e0e\u5e38\u91cf\uff1a<\/h4>\n
struct Id { char * scheme; char * id; };<\/pre>\nstruct ACL { int32_t perms; struct Id id; };<\/pre>\nstruct ACL_vector { int32_t count; struct ACL *data; };<\/pre>\n\n
\n
\n
\u4e0e Interest \u76f8\u5173\u7684\u5e38\u91cf\uff1aZOOKEEPER_WRITE<\/span>, ZOOKEEPER_READ<\/span><\/h4>\n
\u4e0e\u8282\u70b9\u521b\u5efa\u76f8\u5173\u7684\u5e38\u91cf\uff1aZOO_EPHEMERAL<\/span>, ZOO_SEQUENCE<\/span><\/h4>\n
\u4e0e\u8fde\u63a5\u72b6\u6001 Stat \u76f8\u5173\u7684\u5e38\u91cf<\/h4>\n
\n\n
\n ZOOAPI const int <\/span><\/td>\n ZOO_EXPIRED_SESSION_STATE<\/span><\/span><\/td>\n<\/tr>\n \n ZOOAPI const int <\/span><\/td>\n ZOO_AUTH_FAILED_STATE<\/span><\/span><\/td>\n<\/tr>\n \n ZOOAPI const int <\/span><\/td>\n ZOO_CONNECTING_STATE<\/span><\/span><\/td>\n<\/tr>\n \n ZOOAPI const int <\/span><\/td>\n ZOO_ASSOCIATING_STATE<\/span><\/span><\/td>\n<\/tr>\n